Fujifilm Prescale®

Fujifilm Prescale is a unique, affordable and easy to use tool that reveals the distribution and
magnitude of pressure between any two contacting, mating or impacting surfaces. This Tactile
Pressure Indicating Sensor Film is extremely thin (4 to 8 mils) which enables it to conform to
curved surfaces. Fuji Prescale Film is ideal for invasive intolerant environments and tight spaces not
accessible to conventional electronic transducers.

Fujifilm Thermoscale®

Thermoscale® is a unique tool that indicates temperature level and distribution between any
two contacting surfaces. The most unique quality of Thermoscale® is that is goes where no other
IR camera or temperature gauge can ever go - on the surface of the heated object and in between
two contacting surfaces!

Tactilus®

Bodyfitter®

Tactilus® Flex

Ideal for applications/devices that require measurement of repetitive bending motion...
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Tactilus® Free Form sensor system

A "user constructed" tactile surface pressure system that provides unprecedented flexibility...
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Tactilus® Free Form Development Kit

The Free Form® Development Kit is highly economical yet powerful...
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Tactilus® Nano-Polymer Core | H-series Sensor

A nano-polymer based tactile surface sensor. With more accuracy, less drift & better repeatability...
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Tactilus® Nano-Polymer Core | C-series Sensor

A nano-polymer based tactile surface sensor. With more accuracy, less drift & better repeatability...
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Tactilus® Stretch Sensor

A true stretch sensor where the entire sensor element stretches to conform to your surface...
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Auto-Nis®

is a Windows base scanner and software system that enables...
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DigiNip®

is a powerful new system that allows the quick and easy diagnosis...
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EZ-Nip®

is an extremely economical and practical solution for determining...
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Sigma-Nip®

is an electronic nip analysis system that calculates and records nip width...
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Shoe Press Profiler®

The Shoe Press ProfilerÂ® easily allows any technician to quickly and easily capture an...
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Fujifilm Prescale®

Fujifilm Prescale is a unique, affordable and easy to use tool that reveals the distribution...
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Topaq® Pressure Analysis System

Used in conjunction with Fujifilm Prescale pressure indicating films, Topaq provides a quick, yet thorough analysis
of the pressure distribution and magnitude between any two surfaces that come into contact...
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Mold Align®

Mold-Align is a unique, affordable and easy to use tool that reveals pressure distribution between mold platens.
Mold-Align paper, which changes color relative to the amount of contact force. It is an extremely economical
and practical solution for determining proper mold alignment...
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Point Scan

PointScan is a portable Windows based measurement system that enables rapid evaluation of pressure magnitude
at any given point on Fuji Prescale surface pressure indicating film. Simply position PointScan over the area
you wish to analyze and the pressure data is instantly displayed in your Windows software...
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Pressurex-micro®

Pressurex-mirco is a unique, affordable and easy to use tool that reveals relative pressure distribution
between two contacting, mating or impacting surfaces. This pressure indicating sensor film is thin (20 mils)
which enables it to conform to curved surfaces. It is ideal for invasive intolerant environments and
tight spaces not accessible to conventional electronic transducers...
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TemprX®

Fuji Prescale film is a unique, affordable and easy to use tool that reveals the distribution and
magnitude of pressure between any two contacting, mating or impacting surfaces. With the use of TemprX
thermal protection polyimide film it can be used in applications that reach high temperatures...
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Thermex®

Thermex® is a unique temperature indicating material. As thin as a standard sheet of paper, Thermex changes
color to reveal relative temperature distribution between any two contacting surfaces. Upon exposure to
temperature, the Thermex® sheet instantaneously and permanently changes color, with the intensity of
that color directly related to the temperature it was exposed to. This allows Thermex to reveal spot high or
low temperature zones. Thermex® is inexpensive, precise and disposable...
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Encasement Service

Our new Encasement Service for Pressure Indicating Film offers engineers in the flexo, converting and
packaging industries the ability to have Fujifilm Prescale protected so that it can measure contact pressure.

In-House Consulting

Sensor Products now introduces our new in-house surface stress analysis service.
All you need to do is send your part, machine, fixture or assembly to us and weâ€™ll do the rest.
Via video-conferencing you can view the results of our analysis practically in real-time.

Laser Cutting

Leasing Options

Sensor Products offers a variety of products that are available for short and long term lease.
A lease will enable you to gain access to the benefits of our products without the commitment to buy.
Furthermore, after your analysis you can also send the session data back to us for a more in-depth review and critique.

R&D Engineering

Sensor Products has a highly dedicated team of talented engineers with 25 years of combined experience
in the niche discipline of tactile surface sensing. Your project will be supervised by a product manager who
will be your direct contact, and worked upon by our staff consists of material, mechanical, and PHD level electrical engineers.

Background:
Negative-pressure wound therapy is traditionally achieved by attaching
an electrically powered pump to a sealed wound bed and applying
subatmospheric pressure by means of gauze or foam. The Smart Negative
Pressure (SNaP) System (Spiracur, Inc., Sunnyvale, Calif.) is a novel ultraportable
negative-pressure wound therapy system that does not require an electrically
powered pump.

Methods:
Negative pressure produced by the SNaP System, and a powered
pump, the wound vacuum-assisted closure advanced-therapy system (Kinetic
Concepts, Inc., San Antonio, Texas), were compared in vitro using bench-top
pressure sensor testing and microstrain and stress testing with pressure-sensitive
film and micro–computed tomographic scan analysis. In addition, to test in vivo
efficacy, 10 rats underwent miniaturized SNaP (mSNaP) device placement on
open wounds. Subject rats were randomized to a system activation group (approximately
–125 mmHg) or a control group (atmospheric pressure). Wound
measurements and histologic data were collected for analysis.

Conclusions:
The SNaP System and an existing electrically powered negativepressure
wound therapy system have similar biomechanical properties and
functional wound-healing benefits. The potential clinical efficacy of the SNaP
device for the treatment of wounds is supported. (Plast. Reconstr. Surg. 125:
1362, 2010.)

Disclosures:
K.D.F., D.H., and M.P. are current
employees of Spiracur, Inc., but were not employed by
Spiracur at the time of the animal experiments.
M.T.L. and H.P.L. are scientific advisors to Spiracur,
Inc., and have equity interests. The other authors
have no financial interests to disclose.

Negative-pressure wound therapy for treatment
of acute and chronic wounds has
shown great efficacy, and numerous publications
support its clinical use.1–6 In traditional
negative-pressure wound therapy, a gauze or foam
dressing directly contacts the wound bed, and an
electrically powered pump is connected to a
sealed enclosure over the wound. Mechanical
stimulation has been theorized to be a key mechanism
of action in negative-pressure wound therapy,
leading to changes in biochemical signaling
pathways, release of growth factors, and increased
cellular proliferation.1,6–9 Saxena et al. described
how negative pressure draws the wound surface
into the open pores of the wound dressing foam,
which creates regions of variable stress and strain.1
The wound surface in contact with the foamstruts
is compressed, causing compressive stress and
strain. Repeating patterns of high-strain gradients
are created along the surface of the wound
that appear as two-dimensional undulations
across the wound surface.1 In addition, a fluidbased
mechanism has been previously proposed
as a contributing factor to the effectiveness of
negative-pressure wound therapy. Negativepressure
wound therapy removes excess interstitial
fluid, leading to a decrease in interstitial
pressure. Once the interstitial pressure drops
below capillary pressure, capillaries are decompressed
and are able to then reperfuse wound
tissue.6 Thus, an effective negative-pressure
wound therapy device must deliver mechanical
stimulation and handle wound fluid dynamics
within an appropriate negative-pressure range.

Recently, a novel ultraportable negative-pressure
wound therapy system called the SNaP System
was developed. The SNaP System consists of five
basic elements: the vacuum/exudate cartridge, activation/
reset key, hydrocolloid dressing layer, extension
tubing, and a gauze wound interface layer.
Figure 1 shows photographs of the SNaP System
(generation 1.0) used in this study. The commercially
available version (generation 2.0) of the
SNaP System has been further refined and simplified
and can be seen in Figure, Supplemental
Digital Content 1, http://links.lww.com/PRS/A155
(the yellow –75 mmHg model is shown). Compared
with the earlier version of the device, there
was an elimination of the button system, streamlining
of the cartridge design, the addition of a red
cartridge full/air leak indicator, and development
of a customized hydrocolloid dressing layer. To
create negative pressure without an electrically
powered pump, a set of specialized constantforce
springs causes forced air expansion within
the system. A predetermined level of negative
pressure is delivered in a constant fashion as
exudate collects. With exudate inflow, the
unique spring system moves the piston and expands
the system volume to maintain the desired
amount of negative pressure delivered to the
wound. The disposable cartridge is produced
with three different preset pressure levels (approximately
–75, –100, and –125 mmHg), and is
small enough to be worn on a patient’s leg, arm,
or belt and hidden under clothing. Once placed
on the patient, the SNaP System is left in place
between dressing change visits and continues to
deliver negative pressure unless the cartridge
fills with exudates or there is an air leak. If the
patient has a highly exudative wound that fills
the capacity of the cartridge, the patient can
change the cartridge at home. This type of negative-
pressure wound therapy delivery system
has several potential advantages over traditional
pumps, including increased mobility, silent operation,
and decreased cost.

Fig. 1. The ultraportable SNaP Wound Care System (generation 1.0). When the
activation button is depressed, negative pressure is delivered from the retraction
of the sliding seal by constant-force springs to deliver a predetermined level of
negative pressure.

This study compared the SNaP System to a
benchmark negative-pressure wound therapy
product, the wound vacuum-assisted closure advanced-
therapy system device (Kinetic Concepts,
Inc., San Antonio, Texas), an electrical diaphragm-
pump system. The vacuum-assisted closure
device creates negative pressure by removing
mass from the system and uses foam instead of
gauze as the wound interface layer. The vacuumassisted
closure device uses continuous pumping
to compensate for pressure loss from pump backstreaming
and wound exudate inflow. This study
examined the negative pressure delivered by
both systems in a static state and with wound
exudate present. The mechanical stress and
strain patterns produced at the wound bed by
each system was also compared. To evaluate the
effect of negative-pressure wound therapy delivered
by the SNaP System on wound healing in
an in vivo model, a miniaturized version of the
SNaP System (mSNaP System) was created and
tested in a rat open wound model developed by
Isago et al.3 Using a vacuum-assisted closure system
in their model, Isogo et al. found significantly
smaller wound areas in animals treated
with –50, –75, and –125 mmHg of pressure compared
with those treated with no pressure or –25
mmHg of pressure.3

This study used a foam product for both the
vacuum-assisted closure and SNaP System experiments
solely for purposes of comparison of operation
of the two systems. Because both electrical
diaphragm-pump and forced expansion mechanisms
generate negative pressure at the wound
bed, we hypothesized that the end effects of negative
pressure (i.e., exudate evacuation, mechanical
deformation, mechanical stimulation of the
wound, and ultimately faster wound healing)
should be the same.

Materials and methodsBiomechanical TestingPressure Measurement
A simulated wound-dressing enclosure was
constructed by placing a 6 x 6 x 3-cm piece of
GranuFoam (Kinetic Concepts) on a polycarbonate
plate. The foam was covered with a dressing
layer fitted with a pressure delivery port, connected
to either a vacuum-assisted closure device
or SNaP System set to deliver –125 mmHg of negative
pressure [see Figure, Supplemental Digital
Content 2, which demonstrates the biomechanical
pressure testing setup of the SNaP System without
(above) and with (below) exudate simulation,
http://links.lww.com/PRS/A156 (a, negative pressure
provided by either vacuum-assisted closure
(above) or the SNaP System (below) at 125 mmHg;
b, pressure delivery port; c, dressing; d, foam contact
layer; e, data-logging manometer; f, simulated
exudates infused at 5 cc/hour)]. The underside of
the plate was equipped with a separate port where
fluid could be introduced into the system; a datalogging
manometer was connected to monitor
pressure at the underside of the foam. The pressure
delivery system was activated and pressure
level was logged every 20 seconds (4000 over 24
hours = 4000/24/60/60 = 0.0463 per second =
1 every 20 seconds) for 24 hours.

The above procedure was repeated with the addition
of simulated wound exudate, a mixture of 50 percent
glycerol and 50 percent water (see Figure, Supplemental
Digital Content2B, which shows a schematic
of this set-up, http://links.lww.com/PRS/A156). The
mixture was loaded into a 60-cc syringe pump
(New Era Systems, Wantagh, N.Y.) connected to
the underside port of the test plate and infused at
5 cc/hour. The vacuum-assisted closure device or
SNaP System was connected and activated at
–125 mmHg, and pressure measurements were
recorded every 20 seconds for 8 hours. The pressure
delivery systems were massed (in the case of
the vacuum-assisted closure device, only the collection
canister was massed) both before and
after the testing period to measure the amount
of exudate collected.

Contact strain produced by the vacuum-assisted
closure device and SNaP System was evaluated
using micro–computed microtomographic
scanning, following a protocol similar to that developed
by Saxena et al.1 A simulated wound-dressing
enclosure was constructed inside a polyurethane
block 5.5 cm in diameter, and a 3x3x1-cm
sheet of thermoplastic elastomer was placed inside
the block. On top of this sheet, a piece of 3 x 3
x 1-cm GranuFoam was placed. A dressing with
connection tubing was then applied. The enclosure
was then placed on the imaging bed of an Imtek
MicroCAT II CT/MicroSPECT Scanner (Siemens
Corp., New York, N.Y.) with connection tubing leading
outside the scanner (see Figure, Supplemental
Digital Content 3B, which shows a schematic of this
setup, http://links.lww.com/PRS/A157). The tubing
was connected to either a vacuum-assisted closure
device or SNaP System set to produce either –125
mmHg or –75 mmHg of negative pressure, or to no
pressure source. The imaging bed was positioned
and a scan of the enclosure was acquired at a
resolution of 36 x 36 x 41 μm. Five scans were
obtained: no negative pressure, vacuum-assisted
closure at –75 mmHg, vacuum-assisted closure at
–125 mmHg, SNaP System at –75 mmHg, and
SNaP System at –125 mmHg. Scans were reconstructed
in real time using MicroCAT software
and imported into AMIRA (Visage Imaging,
Carlsbad, Calif.) for processing. From the threedimensional
data set, slices parallel and perpendicular
to the simulated wound bed were extracted.
Simulated tissue surfaces were
examined for evidence of deformation (strain)
patterns under the different conditions.

Animal Studies
All animal experiments were performed under
the Stanford University Animal Procedures
and Care Committee’s approved protocol and
were compliant with the guidelines specified in
the National Institutes of Health’s Guide for the Care
and Use of Laboratory Animals. All animals were
housed in the Veterinary Service Center at Stanford
Medical Center with 12-hour light/dark cycles
and ad libitum water and rodent chow
throughout the study period.

Study Groups
Ten Sprague-Dawley rats weighing between 200
and 250 g (similar in size and age to those used by
Isago et al.3) were used in this study, divided randomly
into two groups. The first group had the
mSNaP System placed on their wounds with activation
of negative pressure at approximately –125
mmHg. The second group had the system placed on
their wounds without activation of negative pressure.

mSNaP System Negative-Pressure Wound
Therapy and Sealant System
The mSNaP System used for animal testing is
shown in Figure, Supplemental Digital Content 4,
http://links.lww.com/PRS/A158 (A, constant-force
spring; B, modified syringe body; C, activation
valve; D, syringe plunger seal; E, hydrocolloid skin
dressing; F, on activation, the constant force
springs pull on the plunger, maintaining a constant
level of reduced pressure in the system as
exudates collect). The system consists of a modified
7-cc Epilor syringe (part no. C3601; Qosina,
Edgewood, N.Y.) with an activation valve at one
end and a constant-force spring connected to a
plunger. The syringe chamber is charged by evacuating
air using a 20-ml syringe and closing the
activation valve to lock the plunger in the charged
position. GranuFoam was used as the contact layer
to the wounds. A specially modified hydrocolloid
dressing (DuoDERM; ConvaTec, Skillman, N.J.)
was used as a dressing. The hydrocolloid dressing
had a nozzle integrated into it using a washer
system and ultraviolet light–cured epoxy (Loctite
3311; Henkel, Düsseldorf, Germany). After activation,
a valve was attached to the nozzle dressing.
The valve was then opened to create air/fluid
communication, thus delivering negative-pressure
wound therapy to the wound. Bench testing of the
mSNaP System demonstrated it capable of delivering
–125 ± 10 mmHg of negative pressure.

Surgical Procedure
A surgical wound-healing model was performed
as described previously by Isago et al.3
Briefly, the animals were anesthetized and their
backs were shaved and depilated. Wounds (2.5 x
3.0 cm) were excised through skin and panniculus
carnosus using a scalpel and surgical scissors. The
wounds of each animal were photographed and
measured along the vertical and horizontal
lengths of the body axis. Wounds were dressed
with an interface layer of GranuFoam with a hydrocolloid
cover sheeting, followed by connection
of the mSNaP System. Mastisol ointment (Ferndale
Laboratories, Ferndale, Mich.) was applied to
intact skin of the animals to improve adhesion of
the dressing. The hydrocolloid dressing edges
were reinforced further using large Tegaderm
dressings (3M, St. Paul, Minn.). The syringe portion
of the system was fixed to the animals’ bodies
by half-inch paper tape. Dressings were checked
every 24 hours for all animals, with emptying and
recharging of the system for those randomized
to the system activation group. Wound closure
was defined as complete reepithelialization
without drainage and was evaluated on a daily
basis after discontinuation of SNaP treatment by
a plastic surgeon.

Histologic Evaluation
All dressings were removed on postoperative
days 4 and 7. Punch biopsy specimens (6 mm)
of the central portion of the wound bed were
harvested and fixed in 4% paraformaldehyde.
Animals were not killed to obtain punch biopsy
specimens of wounds. Routine hematoxylin and
eosin staining was used to examine granulation
tissue formation.

Statistical Analysis
To assess group differences, a two-sample t test
(two-tailed) or modified t test for uneven variance
was applied. The values were considered to be
significant at a level of p < 0.05.

RESULTSMechanical Testing DataSimilar Pressure Delivered by the SNaP
System and the Vacuum-Assisted Closure Device
When No Exudate Is Present
When set at –125 mmHg and tested over a
period of 24 hours, the vacuum-assisted closure
device delivered an average pressure of –124.9 ±
1.3 mmHg. The SNaP System delivered –120.7 ±
1.18 mmHg. Both systemsmaintained a steady level
of negative pressure throughout the test period, with
very small degrees of variability, as demonstrated in
Figure 2. The pressures were measured over the
duration of the test (4000 time point measurements).
The stated standard deviations were calculated
from all data points taken during the respective
tests and reflecthowwell the device (vacuum-assisted
closure advanced-therapy system or SNaP Cartridge)
maintained a steady-state pressure.

Fig. 2. Plot of pressure delivered under static state for SNaP System and vacuumassisted
closure (VAC). The vacuum-assisted closure device delivered an average pressure
of –124.9±1.3mmHg,whereas theSNaPSystem delivered –120.7±1.18mmHg.
Both devices were able to maintain a steady level of negative pressure throughout the
test period and demonstrated a very small degree of variability.

Similar Pressure Delivered by the SNaP
System and the Vacuum-Assisted Closure Device
When Exudate Is Present
Eight hours of pressure measurements were
recorded during the infusion of simulated exudate
at the rate of 5 cc/hour. The average pressure
delivered by the vacuum-assisted closure device
was 123.2 ± 0.8 mmHg, compared with 121.7 ±
3.1 mmHg delivered by the SNaP System. The
pressure signal of the SNaP System, although confined
to a tight band of negative pressure, exhibited
a sawtooth pattern characteristic of minute
movements of the constant-force spring mechanism
to correct for pressure loss during exudate
entry. A total of 40 cc of exudate was infused into
the simulated wound during the duration of the
test. The vacuum-assisted closure device collected
31 g, whereas the SNaP System collected
35 g of exudate. Figure 3 demonstrates that both
systems delivered and maintained a steady level
of negative pressure under conditions of fluid
introduction. The pressures were measured
over the duration of the test. The stated standard
deviations were calculated from all data
points taken during the respective tests and reflect
how well the device (vacuum-assisted closure
advanced-therapy system or SNaP Cartridge)
maintained a steady-state pressure.

Fig. 3. Plot of pressure delivered during exudate test for SNaP System and the vacuum-
assisted closure (VAC) device. Average pressure delivered by the vacuum-assisted
closure device was –123.2 ± 0.8 mmHg; the SNaP System delivered –121.7 ± 3.1
mmHg. Both devices were able to deliver and maintain a steady level of negative
pressure, even under conditions of fluid introduction.

Similar Contact Stress Patterns Delivered by
the SNaP System and the Vacuum-Assisted
Closure Device
The SNaP System and vacuum-assisted closure
device produced similar contact stress profiles for
equivalent pressure levels, as measured by micropressure-
sensitive film (Fig. 4). The patterns of
contact stress demonstrated that both systems conducted
negative pressure through the foam and
produced very similar wound surface stress gradients.
The pressure distribution image is qualitative,
showing relative areas of high stress and low
stress. Further quantitative analysis of the data was
precluded by the sensitivity limit of the pressuresensitive
film used.

Fig. 4. Biomechanical testing, pressure measurement. (Left and second from left) Raw images of pressure-sensitive film recovered
from under foam for vacuum-assisted closure (VAC) and the SNaP System at –75mmHgand –125 mmHg. Dark regions denote areas
of high compressive stress in contact with film, and light regions denote no contact. Note that both the SNaP System and the
vacuum-assisted closure device produce characteristic repeating patterns on length scales, consistent with foam pore size. (Right
and second from right) Color-enhanced detail from pressure-sensitive films.

Similar Contact Strain Patterns Delivered by
the SNaP System and the Vacuum-Assisted
Closure Device
Notable features of the micro–computed tomographic
scans are shown in Figure 5. This figure
shows the foam microstructure to be clearly visible.
Without delivery of negative pressure, the simulated
wound bed/foam interface is smooth. With
delivery of negative pressure at –75mmHgor –125
mmHg by either the SNaP System or the vacuumassisted
closure device, the characteristic pattern
of deformation that occurs with negative pressure
occurs at the simulated wound bed/foam interface.
This pattern matches the predicted stress and
strain pattern of undulation described and demonstrated
by Saxena et al.1 No discernible difference
in the microdeformation patterns was observed
between the two pressures tested for either
the SNaP System or vacuum-assisted closure–
treated experiments. Furthermore, the patterns of
deformation appeared nearly identical for both
the SNaP System and vacuum-assisted closure at
the pressure levels tested. Because this was a qualitative
measure, no further quantitative analysis
was performed.

Animal Testing DataWounds Healed Faster with the Activated
mSNaP System
Animals treated with themSNaPSystem had a 51
percent reduction in wound size compared with a 12
percent reduction in wound size of control subjects
at 7 days (p < 0.05) (Fig. 6). Complete reepithelialization
also occurred faster than in control subjects
(21 days versus 32 days; p<0.05), as shown in Figure 7.
See Figure, Supplemental Digital Content 5, which
shows representative wounds at postoperative days 0
and 7, http://links.lww.com/PRS/A159 (note the increased
granulation tissue and smaller size of the
activated system–treated wounds compared with atmospheric
controls). Comparison of animals treated
with the mSNaP System to data from the study by
Isago et al. using the vacuum-assisted closure device
in the same animal model reveal very similar results.
ThemSNaPSystem–treated wounds demonstrated a
51 percent decrease in wound size, which is comparable
to the reported 40 percent decrease in wound
size observed for vacuum-assisted closure–treated
animals at 1 week.3 Control animals treated with
atmospheric pressure in this study and the study by
Isago et al. were 12 percent and 14 percent surface
area size reduction, respectively.3

Wounds Had Greater Granulation Tissue
with the Activated mSNaP System
Similar to previous reports for the vacuumassisted
closure device,10 the mSNaP System promoted
granulation tissue formation compared
with controls, noted by gross examination of the
wounds (see Figure, Supplemental Digital Content
5, http://links.lww.com/PRS/A159) and by hematoxylin
and eosin staining on postoperative
days 4 and 7 (Figs. 8 and 9).

There were no fatalities, wound infections, or
other significant complications from treatment in
any of the animal studies. However, the DuoDERM seal
did fail in two rat subjects (on postoperative
days 3 and 6). The seal was reestablished
with the addition of Tegaderm and paper tape to
the area of dressing dehiscence.

DISCUSSION
In this study, a novel, ultraportable negativepressure
wound therapy system was evaluated. The
mechanical testing experiments demonstrated
that the SNaP System delivers steady negative pressure
to wound beds with and without exudate
present in a fashion similar to the vacuum-assisted
closure device. The mechanical stress and strain
patterns produced by the SNaP System were also
comparable to those created by the vacuum-assisted
closure device. Thus, from a pressure delivery
standpoint, the negative pressure delivered by
both systems was essentially identical. Based on
these findings alone, the SNaP System would be
expected to deliver the same functional benefits to
a wound as the vacuum-assisted closure device. To
test this hypothesis, the SNaP System was evaluated
in vivo using a rat open wound model. The SNaP
System delivered effective negative-pressure
wound therapy, evidenced by increased granulation
tissue formation and faster healing, consistent
with published results using vacuum-assisted
closure in the same animal model.3

Although human efficacy data are still needed
for the SNaP System, and although foam is currently
not recommended for use with the SNaP
System, the biomechanical and in vivo data suggest
that the SNaP System may have efficacy equal
to that of vacuum-assisted closure for some
wounds. This study was performed in a rodent
model, and many differences exist between acute
rodent wound healing and wound-healing problems
found in humans. In addition, only a single
pressure level, –125 mmHg, was tested in vivo.
Other pressure levels may have worse, equal, or
better wound repair outcomes. However, the
potential benefits of a silent, disposable, less
expensive, and less cumbersome negative-pressure
wound therapy system may prove to be valuable
to clinicians.

ACKNOWLEDGMENTS
This work was supported by Spiracur, the Oak Foundation,
and the Hagey Laboratory for Pediatric Regenerative
Medicine. Portions of the experiment (micro–computed
tomographic strain evaluation) were performed at the
Stanford Center for Innovation in In Vivo Imaging with
collaboration from Dr. Timothy Doyle (Stanford Center for
Innovation in In Vivo Imaging). Spiracur and SNaP are
trademarks of Spiracur, Inc. All rights reserved.